In the AA sample, the most significant SNP that confers a protective effect is rs555018 in CHRNA5 (p = 0.045, OR = 0.79 (0.63–0.99)). This SNP is not correlated with rs16969968 in AAs (r2 = 0.02), though |D′| = 1. It is highly correlated with rs588765, which has been shown to affect expression of CHRNA5 in EAs [33, 34] (r2 = 0.99 in our AA sample and 0.999 in EAs). Therefore the evidence for association between rs588765 and nicotine dependence in AAs is similar (p = 0.055, OR = 0.80 (0.63–1.00)) to that found for rs555018. In contrast, neither rs555018 nor rs588765 is associated with nicotine dependence in the EAs.
